For the second straight quarter, Roll Call’s list of most vulnerable governorships has been volatile. [IMGCAP(1)]

As always, we rank the contests by the likelihood of partisan change, using current factors, not theoretical candidacies. This time, we’re setting aside the 2005 contests, New Jersey and Virginia, which are almost upon us.

1. New York
Vacating seat: George Pataki (R)
Last ranking: 1

Pataki has decided against seeking a fourth term, and Democratic state Attorney General Eliot Spitzer remains the strong favorite. While Spitzer may face a primary challenge from Nassau County Executive Tom Suozzi (D), the GOP field is even messier, with former Massachusetts Gov. William Weld (R) potentially facing several others in the primary, most notably Tom Golisano, a wealthy independent who has just become a Republican and may run.

2. Iowa
Vacating seat: Tom Vilsack (D)
Last ranking: 4

Iowa moves up two notches amid growing GOP unity behind Rep. Jim Nussle (despite his ties to indicted GOP Rep. Tom DeLay of Texas) and a continuing lack of enthusiasm about the Democratic field, which includes state Economic Development Director Michael Blouin, Secretary of State Chet Culver, state Rep. Ed Fallon, Agriculture Secretary Patty Judge and engineer Sal Mohamed. Democrats hope an early primary (June 6) will leave the party time to regroup.

3. Massachusetts
Incumbent: Mitt Romney (R)
Last ranking: 5

With Romney all but out the door, Massachusetts remains prime takeover territory for a Democrat. But which one?

State Attorney General Thomas Reilly is the best-known and best-financed contender, but his lack of charisma and centrist views could spell trouble in a Democratic primary. Former Clinton administration official Deval Patrick has the potential to break through, but hasn’t yet. Secretary of State William Galvin, if he runs, has some of Reilly’s drawbacks.

Lt. Gov. Kerry Healey (R) saw her chances improve when health care executive Charlie Baker decided to skip the

race, though Christy Mihos, a libertarian-leaning maverick, is weighing a run. Both Healey and Mihos are well-heeled, but a September University of Massachusetts poll found Reilly beating Healey 53 percent to 28 percent, and Galvin and Patrick winning by smaller margins.

4. Ohio
Vacating seat: Bob Taft (R)
Last ranking: 3

Taft’s approval ratings remain in the dumps, but first, Democrats must decide between Rep. Ted Strickland and Columbus Mayor Michael Coleman. A Columbus Dispatch survey found a whopping 55 percent of primary voters undecided.

On the GOP side, Secretary of State Ken Blackwell leads state Attorney General Jim Petro and state Auditor Betty Montgomery. That cheers Democrats, who expect Blackwell, a staunch conservative, to be the easiest to beat. But Democrats shouldn’t break out the bubbly just yet: Even the GOP’s weakened infrastructure may be able to outfight the Democrats on the ground, insiders say.

5. Oregon
Incumbent: Ted Kulongoski (D)
Last ranking: 9

Kulongoski, already fending off primary challenges by Lane County Commissioner Peter Sorenson and state Sen. Vicki Walker, drew two new possible Democratic adversaries in September: state Sen. Rick Metsger and former state Treasurer Jim Hill. There’s even talk, largely but not entirely dismissed, of former Gov. John Kitzhaber (D) running.

At the same time, Kulongoski has to worry about the GOP. Going into the fall, attorney Ron Saxton and state party Chairman Kevin Mannix were both outraising the governor. State Sen. Jason Atkinson (R) is also in the race.

6. Michigan
Incumbent: Jennifer Granholm (D)
Last ranking: 8

With Michigan’s economy still weak, 49 percent of voters disapproved of Granholm’s job performance in a September EPIC-MRA poll — her worst numbers ever — with only 46 percent approving. And just 35 percent said they would definitely re-elect her. Fortunately for Granholm, her Republican rival, businessman Dick DeVos, is far from closing the deal. EPIC-MRA had Granholm leading DeVos 50 percent to 30 percent, and even a Republican poll in September had her up 47 percent to 33 percent.

7. California
Incumbent: Arnold Schwarzenegger (R)
Last ranking: 6

The Governator’s numbers remain weak, but there’s a growing feeling, even among Democrats, that knocking him off won’t be easy. After all, former Gov. Gray Davis (D) won re-election in 2002 despite his unpopularity. And while liberal state Treasurer Phil Angelides (D) and moderate state Controller Steve Westly (D) edge Schwarzenegger in the polls, they may not have the stature to get their message out against a celebrity in full campaign mode.

Schwarzenegger’s slate of ballot initiatives this fall might be a win-win: If he prevails, he looks like a genius, and if he loses, he’ll be able to recast himself as the victimized outsider trying to shake things up.

8. Alabama
Incumbent: Bob Riley (R)
Last ranking: Unranked

The shoe has dropped: Roy Moore, the Ten Commandments judge, is in the race.

Surprisingly, the once-weakened Riley, bolstered by his post-Hurricane Katrina performance, led Moore by 19 points among likely GOP primary voters, an October Mobile Register-University of South Alabama poll found — a switch from Moore’s 8-point lead in January. (State Sen. Harri Anne Smith may also join the GOP fray.)

The Democratic primary pits Lt. Gov. Lucy Baxley against former Gov. Don Siegelman. Both trailed Riley by double digits in another October Register-USA poll, though Baxley beat Moore by 7 points and Siegelman tied him. With this kind of field, anything can happen.

9. Maryland
Incumbent: Bob Ehrlich (R)
Last ranking: 7

This race has been overshadowed by a hot Senate contest, which suggests that Ehrlich is safer now than he was earlier this year. But that should change once Democrats finally choose between Baltimore Mayor Martin O’Malley and Montgomery County Executive Doug Duncan. Still, Democrats may be underwhelmed by what comes out of the legislature’s investigation into cronyism and hardball tactics by the Ehrlich administration, one Democrat said.

10. Wisconsin
Incumbent: Jim Doyle (D)
Last ranking: 12

Republicans remain optimistic about Wisconsin, with two challengers, Rep. Mark Green (R) and Milwaukee County Executive Scott Walker, reporting solid fundraising numbers. But Doyle was boosted by an early-October Wisconsin Policy Research Institute poll: He led Green, 46 percent to 33 percent, and Walker, 50 percent to 31 percent. This swing-state race should remain volatile to the end, however.

Just below the top 10:

11. Illinois
Incumbent: Rod Blagojevich (D)
Last ranking: Unranked

Blagojevich is lucky that former GOP Gov. Jim Edgar decided against running, but his administration is still mired in an ethical and legal mess. An October Chicago Tribune-WGN poll found 42 percent opposing his re-election and only 35 percent supporting. If the drip-drip continues, even Illinois’ dysfunctional GOP might capitalize.

12. Arkansas
Vacating seat: Mike Huckabee (R)
Last ranking: 10 (tie)

Democratic state Attorney General Mike Beebe has had a rough few weeks, forced in his AG capacity to defend legislative pork and judicial inaction on school spending. The GOP also attacked him for not working harder to fight an energy rate hike, noting that he’s taken donations from utilities. Beebe may also face primary opposition from Bill Halter, the former acting Social Security Commissioner under President Bill Clinton. All of this helps former GOP Rep. Asa Hutchinson, who had been lagging in fundraising early on.

Climbers:

Pennsylvania. Keystone State governors seeking a second term aren’t supposed to face top-tier competition, but the GOP field continues to gain momentum, especially football Hall of Famer Lynn Swann and former Lt. Gov. Bill Scranton. While both trailed Gov. Ed Rendell (D) by double digits in a recent Quinnipiac poll, and although 48 percent of voters said the governor deserves a second term (41 percent said he doesn’t), that’s unusually promising by the state’s historical standards. Despite weakness outside the Philadelphia area, Rendell’s residual popularity in the southeast may still win him a second term. Oklahoma. Gov. Brad Henry (D) will have a genuine race now that Rep. Ernest Istook (R) is running. But even a GOP poll in September had Istook down by 8 points, and the early consensus is that Istook is neither sufficiently well-liked, nor does he have a large enough geographical base, to oust a governor who hasn’t made many mistakes.

Volatile:

Georgia. Gov. Sonny Perdue (R) won wide praise for his response to Hurricane Katrina, then drew fire for urging a two-day closure of schools to preserve diesel fuel. News accounts later detailed how agribusiness lobbyists pushed that decision, with electoral fallout that’s still evolving. Meanwhile, Secretary of State Cathy Cox (D), who’s fighting Lt. Gov. Mark Taylor for the Democratic nomination, has taken lumps for a television campaign about insurance scams that critics charge is mostly self-promotion. A wild card: the widening ethical scrutiny of lieutenant governor candidate Ralph Reed (R).

Minnesota. With an unruly legislative session behind him, Gov. Tim Pawlenty (R) is getting a breather, but he could face Attorney General Mike Hatch or wealthy developer Kelly Doran (among others) in the general. Hatch led Pawlenty by 3 points in a recent Zogby poll.

Nevada. Rep. Jim Gibbons (R) remains the frontrunner, but he’s continued to underwhelm. With Assembly Speaker Richard Perkins (D) skipping the race, the Democrats are left with Senate Minority Leader Dina Titus (too liberal and too Las Vegas, say skeptics) and Henderson Mayor Jim Gibson (who may be too moderate to win the primary).

Declining:

Maine. Gov. John Baldacci (D), bolstered by a partial base-closing victory, has recovered since May. And he got a break when 2002 GOP nominee Peter Cianchette decided against another run, leaving a field of lesser-known Republicans.